Adjustable mattress foundations are utilized to vary the shape of a mattress supported thereon in accordance with a user's comfort level. Such foundations are operable, for example, to incline a portion of the mattress associated with the user's head and shoulders, and another portion of the mattress associated with the user's legs and feet. Vibration motors are also typically utilized with adjustable mattress foundations to impart massaging vibrations to portions of the mattress associated with the user's back and legs.